The present invention relates to maintenance procedures for reducing maintenance cost of cyclically operable machines and in particular to copy production machines of the transfer electrographic type or other forms of document reproduction or printing machines.
Copy production machines, particularly the ones of the transfer electrographic type, as well as ink jet and other forms of transfer image recording, usually contain a multiplicity of interacting mechanical, electromechanical, and electrical portions. Error conditions within such a machine can create symptoms which are misleading. Maintenance personnel diagnosing troubles in such machines have to comprehend all of the possible interactions. Analogous procedures have been practiced data processing art for many years. The inclusion of automatic diagnostic programs in computerized control of copy production machines can materially reduce maintenance time by increasing the effectiveness of maintenance personnel as it has in the data processing art. Such diagnostics can operate the entire machine or separately operate major portions of the machine. In general, data processing analysis has resulted in fully automatic diagnostics which are useful in data processing systems of all types including machine control. Portions of the machine or system being controlled can be selectively exercised independently from the rest of the machine for comprehensive diagnostics, or such diagnostics in combination with error status reporting techniques, which are notoriously old, provide a valuable tool for maintaining diverse machines. However, some intermittents and other problems may not be fully diagnosable in a minimal time, even with such full diagnostics. Accordingly, further diagnostic power is yet needed for efficient maintenance of complex machines, particularly of such machines involving electromechanical and electrical circuit interactions.